The variability of Seyfert 1.8 and 1.9 galaxies at 1.6 microns

We present a study of Seyfert 1.5-2.0 galaxies observed at two epochs with the Hubble Space Telescope (HST) at 1.6 mu m We find that unresolved nuclea r emission from nine of 14 nuclei varies at the level of 10%-40% on timesca les of 0.7-14 months, depending upon the galaxy. A control sample of Seyfer t galaxies lacking unresolved sources and galaxies lacking Seyfert nuclei s how less than 3% instrumental variation in equivalent aperture measurements . This proves that the unresolved sources are nonstellar and associated wit h the central parsecs of active galactic nuclei. Unresolved sources in Seyf ert 1.8 and 1.9 galaxies are not usually detected in HST optical surveys; h owever, high angular resolution infrared observations will provide a way to measure time delays in these galaxies.